Printing cylinders are prepared by plating a layer of metal, such as copper, on the surface of the cylinder, for subsequent etching or engraving operations and for printing operations therewith. Conventionally, the printing cylinders have projecting shaft portions which, in the plating operation, are engaged with support hub units on the outside of side walls of a plating tank. At least one hub unit is connected to a drive source and a slip ring unit is associated with at least one hub unit for connection to one terminal of a current supply source. In such apparatus, the shafts and the ends of the cylinders have been protected from corrosion by winding a tape therearound prior to the plating operation. With this taping process, results have been obtained which have heretofore seemed to have been reasonably satisfactory and, so far as is known, no efforts have been directed by others toward improvements of the process.